1. Field of the Invention
The invention relates to a method for brazing aluminum materials and an apparatus used therein, the aluminum materials being suited for manufacture of various goods such as heat exchangers which are generally made by the brazing process.
The word "aluminum" used in this specification is meant to include its alloys.
2. Description of Prior Art
Flux brazing method which uses a proper flux is widely employed in cases wherein the vacuum brazing is not available, in order to braze the aluminum parts of such heat exchangers made of aluminum and used as a radiator in automobiles, as an evaporator or condenser for car air-conditioners, or as elemental units of other electric or mechanical apparatus.
In the known flux brazing method, it has been a general practice to disperse first the flux in water or solvent so as to prepare a suspension. The suspension is then sprayed or showered onto the aluminum materials or parts which are to be bonded to each other, or they are immersed in the suspension which is to be applied thereto. After the aluminum parts are dried to remove water contained in the suspension, said parts are subsequently heated to a predetermined temperature in a non-oxidizing atmosphere so that a brazing agent is molten and the brazing is effected.
Productivity of such a known practice is however significantly low because it needs some operations for application of the suspension and also for drying the parts to which it has been applied. A drying oven used to dry said parts has rendered the equipment large-sized to a disadvantageous degree. It has been somewhat cumbersome to control the temperature of said suspension and the applied quantity thereof. Further, the aluminum materials are in general given an excessive amount of the flux so that brazing ovens are fouled therewith and/or the flux molten in the brazing ovens makes a deposit therein. Therefore, the cleaning or overhauling of the brazing ovens should be done at short intervals. The flux applied to the aluminum materials in the manner as mentioned above will remain as gray or white blots on the surfaces thereof after the brazing process is completed. Those blots not only make uneven the surface color of said materials but also make worse the smoothness or homogeneity of a subsequent surface treatment. It is very difficult to remove the remaining flux from the surfaces of aluminum materials because it is fixed thereto unseparably.